/*
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html.
 *
 * This file is a derivative of code released under the terms listed below.
 *
 */
/*
*  Copyright (c) 2013,
*      Tobias Blaschke <code@tobiasblaschke.de>
*  All rights reserved.

*  Redistribution and use in source and binary forms, with or without
*  modification, are permitted provided that the following conditions are met:
*
*  1. Redistributions of source code must retain the above copyright notice,
*     this list of conditions and the following disclaimer.
*
*  2. Redistributions in binary form must reproduce the above copyright notice,
*     this list of conditions and the following disclaimer in the documentation
*     and/or other materials provided with the distribution.
*
*  3. The names of the contributors may not be used to endorse or promote
*     products derived from this software without specific prior written
*     permission.
*
*  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
*  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
*  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
*  ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
*  LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
*  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
*  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
*  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
*  CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
*  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
*  POSSIBILITY OF SUCH DAMAGE.
*/
package com.ibm.wala.dalvik.ipa.callgraph.propagation.cfa;

import com.ibm.wala.cfg.ControlFlowGraph;
import com.ibm.wala.classLoader.CallSiteReference;
import com.ibm.wala.classLoader.CodeScanner;
import com.ibm.wala.classLoader.IClass;
import com.ibm.wala.classLoader.IMethod;
import com.ibm.wala.classLoader.NewSiteReference;
import com.ibm.wala.dalvik.ipa.callgraph.androidModel.AndroidModel;
import com.ibm.wala.dalvik.ipa.callgraph.androidModel.MicroModel;
import com.ibm.wala.dalvik.ipa.callgraph.androidModel.stubs.ExternalModel;
import com.ibm.wala.dalvik.ipa.callgraph.androidModel.stubs.SystemServiceModel;
import com.ibm.wala.dalvik.ipa.callgraph.androidModel.stubs.UnknownTargetModel;
import com.ibm.wala.dalvik.util.AndroidComponent;
import com.ibm.wala.dalvik.util.AndroidEntryPointManager;
import com.ibm.wala.ipa.callgraph.AnalysisOptions;
import com.ibm.wala.ipa.callgraph.CGNode;
import com.ibm.wala.ipa.callgraph.Context;
import com.ibm.wala.ipa.callgraph.ContextKey;
import com.ibm.wala.ipa.callgraph.IAnalysisCacheView;
import com.ibm.wala.ipa.callgraph.propagation.AbstractTypeInNode;
import com.ibm.wala.ipa.callgraph.propagation.SSAContextInterpreter;
import com.ibm.wala.ipa.cha.IClassHierarchy;
import com.ibm.wala.ipa.summaries.SummarizedMethod;
import com.ibm.wala.ssa.DefUse;
import com.ibm.wala.ssa.IR;
import com.ibm.wala.ssa.IRView;
import com.ibm.wala.ssa.ISSABasicBlock;
import com.ibm.wala.ssa.SSAInstruction;
import com.ibm.wala.types.FieldReference;
import com.ibm.wala.types.MethodReference;
import com.ibm.wala.types.TypeReference;
import com.ibm.wala.util.CancelException;
import java.util.EnumSet;
import java.util.Iterator;
import java.util.Set;

/**
 * An {@link SSAContextInterpreter} that redirects functions that start Android-Components.
 *
 * <p>The Starter-Functions (listed in IntentStarters) are replaced by a Model that emulates Android
 * Lifecycle based on their Target (Internal, External, ...): A wrapper around the single models is
 * generated dynamically (by the models themselves) to resemble the signature of the replaced
 * function.
 *
 * <p>Methods are replacement by generating a adapted Intermediate Representation of this function
 * on every occurrence of a call to it.
 *
 * @see com.ibm.wala.dalvik.ipa.callgraph.propagation.cfa.IntentContextSelector
 * @see com.ibm.wala.dalvik.ipa.callgraph.propagation.cfa.IntentStarters
 * @see com.ibm.wala.dalvik.ipa.callgraph.androidModel.MicroModel
 * @see com.ibm.wala.dalvik.ipa.callgraph.androidModel.stubs.ExternalModel
 * @author Tobias Blaschke &lt;code@tobiasblaschke.de&gt;
 * @since 2013-10-14
 */
public class IntentContextInterpreter implements SSAContextInterpreter {
  private final IntentStarters intentStarters;
  private final IClassHierarchy cha;
  private final AnalysisOptions options;
  private final IAnalysisCacheView cache;

  public IntentContextInterpreter(
      IClassHierarchy cha, final AnalysisOptions options, final IAnalysisCacheView cache) {
    this.cha = cha;
    this.options = options;
    this.cache = cache;
    this.intentStarters = new IntentStarters(cha);
  }

  /** Read possible targets of the intents Infos. */
  private AndroidComponent fetchTargetComponent(final Intent intent, final IMethod method) {
    assert (method != null);
    assert (intentStarters.getInfo(method.getReference()) != null)
        : "No IntentStarter for Method " + method + ' ' + intent;
    if (intent.getComponent() != null) {
      return intent.getComponent();
    } else if (intent.getType() == Intent.IntentType.SYSTEM_SERVICE) {

      return AndroidComponent.UNKNOWN;
    } else {
      final Set<AndroidComponent> possibleTargets =
          intentStarters.getInfo(method.getReference()).getComponentsPossible();
      if (possibleTargets.size() == 1) {
        final Iterator<AndroidComponent> it = possibleTargets.iterator();
        return it.next();
      } else {
        // TODO: Go interactive and ask user?
        final Iterator<AndroidComponent> it = possibleTargets.iterator();
        final AndroidComponent targetComponent = it.next();
        return targetComponent;
      }
    }
  }

  private static TypeReference getCaller(final Context ctx, final CGNode node) {
    if (ctx.get(ContextKey.CALLER) != null) {
      System.out.println("CALLER CONTEXT" + ctx.get(ContextKey.CALLER));
      return node.getMethod().getReference().getDeclaringClass();
    } else if (ctx.get(ContextKey.CALLSITE) != null) {
      System.out.println("CALLSITE CONTEXT" + ctx.get(ContextKey.CALLSITE));
      return node.getMethod().getReference().getDeclaringClass();
    } else if (ctx.get(ContextKey.RECEIVER) != null) {
      final AbstractTypeInNode aType = (AbstractTypeInNode) ctx.get(ContextKey.RECEIVER);
      return aType.getConcreteType().getReference();
    } else {
      return node.getMethod()
          .getReference()
          .getDeclaringClass(); // TODO: This may not necessarily fit!
    }
  }

  /**
   * Generates an adapted IR of the managed functions on each call.
   *
   * @param node The function to create the IR of
   * @throws IllegalArgumentException on a node of null
   */
  @Override
  public IR getIR(CGNode node) {
    if (node == null) {
      throw new IllegalArgumentException("node is null");
    }
    assert understands(node); // Should already have been checked before
    {
      // TODO: CACHE!
      final Context ctx = node.getContext();
      final TypeReference callingClass = getCaller(ctx, node);

      if (ctx.get(Intent.INTENT_KEY) != null) {
        try { // Translate CancelException to IllegalStateException
          final Intent inIntent = (Intent) ctx.get(Intent.INTENT_KEY); // Intent without overrides
          final Intent intent =
              AndroidEntryPointManager.MANAGER.getIntent(inIntent); // Apply overrides
          final IMethod method = node.getMethod();

          final AndroidModel model;
          final IntentStarters.StartInfo info;
          Intent.IntentType type = intent.getType();
          if (intent.getAction().equals(Intent.UNBOUND)) {
            type = Intent.IntentType.UNKNOWN_TARGET;
          }
          { // Fetch model and info
            switch (type) {
              case INTERNAL_TARGET:
                info = intentStarters.getInfo(method.getReference());

                model = new MicroModel(this.cha, this.options, this.cache, intent.getAction());

                break;
              case SYSTEM_SERVICE:
                info =
                    new IntentStarters.StartInfo(
                        node.getMethod().getReference().getDeclaringClass(),
                        EnumSet.of(Intent.IntentType.SYSTEM_SERVICE),
                        EnumSet.of(AndroidComponent.SERVICE),
                        new int[] {1});

                model =
                    new SystemServiceModel(this.cha, this.options, this.cache, intent.getAction());

                break;
              case EXTERNAL_TARGET:
                info = intentStarters.getInfo(method.getReference());

                model =
                    new ExternalModel(
                        this.cha, this.options, this.cache, fetchTargetComponent(intent, method));

                break;
              case STANDARD_ACTION:
                // TODO!
                // In Order to correctly evaluate a standard-action we would also have to look
                // at the URI of the Intent.
              case UNKNOWN_TARGET:
                info = intentStarters.getInfo(method.getReference());

                model =
                    new UnknownTargetModel(
                        this.cha, this.options, this.cache, fetchTargetComponent(intent, method));

                break;
              case IGNORE:
                return null;
              default:
                throw new java.lang.UnsupportedOperationException(
                    "The Intent-Type "
                        + intent.getType()
                        + " is not known to IntentContextInterpreter");
                // return method.makeIR(ctx, this.options.getSSAOptions());
            }

            assert (info != null) : "IntentInfo is null! Every Starter should have an StartInfo...";
          } // of model and info

          final SummarizedMethod override =
              model.getMethodAs(method.getReference(), callingClass, info, node);
          return override.makeIR(ctx, this.options.getSSAOptions());
        } catch (CancelException e) {
          throw new IllegalStateException("The operation was canceled.", e);
        }
      } else {
        // This should _not_ happen: IntentContextSelector should always create an IntentContext.
        //
        final IMethod method = node.getMethod();
        final IntentStarters.StartInfo info = intentStarters.getInfo(method.getReference());
        assert (info != null)
            : "IntentInfo is null! Every Starter should have an StartInfo... - Method "
                + method.getReference();
        final Intent intent = new Intent(Intent.UNBOUND);
        final AndroidComponent targetComponent = fetchTargetComponent(intent, method);

        try {
          final UnknownTargetModel model =
              new UnknownTargetModel(this.cha, this.options, this.cache, targetComponent);
          final SummarizedMethod override =
              model.getMethodAs(
                  method.getReference(),
                  callingClass,
                  intentStarters.getInfo(method.getReference()),
                  node);
          return override.makeIR(ctx, this.options.getSSAOptions());
        } catch (CancelException e) {
          throw new IllegalStateException("The operation was canceled.", e);
        }
      }
    }
  }

  @Override
  public IRView getIRView(CGNode node) {
    return getIR(node);
  }

  /**
   * If the function associated with the node is handled by this class.
   *
   * @throws IllegalArgumentException if the given node is null
   */
  @Override
  public boolean understands(CGNode node) {
    if (node == null) {
      throw new IllegalArgumentException("node is null");
    }
    final MethodReference target = node.getMethod().getReference();
    return (intentStarters.isStarter(target));
  }

  @Override
  public Iterator<NewSiteReference> iterateNewSites(CGNode node) {
    if (node == null) {
      throw new IllegalArgumentException("node is null");
    }
    assert understands(node); // Should already have been checked before
    {
      final IR ir = getIR(node); // Speeeed
      return ir.iterateNewSites();
    }
  }

  @Override
  public Iterator<CallSiteReference> iterateCallSites(CGNode node) {
    if (node == null) {
      throw new IllegalArgumentException("node is null");
    }
    assert understands(node); // Should already have been checked before
    {
      final IR ir = getIR(node); // Speeeed
      return ir.iterateCallSites();
    }
  }

  //
  // Satisfy the rest of the interface
  //
  @Override
  public ControlFlowGraph<SSAInstruction, ISSABasicBlock> getCFG(CGNode node) {
    assert understands(node);
    return getIR(node).getControlFlowGraph();
  }

  @Override
  public int getNumberOfStatements(CGNode node) {
    assert understands(node);
    return getIR(node).getInstructions().length;
  }

  @Override
  public DefUse getDU(CGNode node) {
    assert understands(node);
    return new DefUse(getIR(node));
  }

  @Override
  public boolean recordFactoryType(CGNode node, IClass klass) {
    // this.
    return false;
  }

  @Override
  public Iterator<FieldReference> iterateFieldsWritten(CGNode node) {
    assert understands(node);

    final SSAInstruction[] statements = getIR(node).getInstructions();

    return CodeScanner.getFieldsWritten(statements).iterator();
  }

  @Override
  public Iterator<FieldReference> iterateFieldsRead(CGNode node) {
    assert understands(node);

    final SSAInstruction[] statements = getIR(node).getInstructions();

    return CodeScanner.getFieldsRead(statements).iterator();
  }
}
